Open AccessA Test of Ice Self-Collection Kernels Using Aircraft Data
Author(s) -
Paul R. Field,
Andrew J. Heymsfield,
Aaron Bansemer
Publication year - 2006
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/jas3653.1
Subject(s) - cirrus , ice crystals , kernel (algebra) , particle size distribution , environmental science , physics , atmospheric sciences , particle size , geology , meteorology , mathematics , combinatorics , paleontology
Aircraft observations from the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL)–Florida Area Cirrus Experiment (FACE) campaign obtained in the anvil of a large convective storm from 26 July 2002 are presented. During this flight a Lagrangian spiral descent was made, allowing the evolution of the ice particle size distribution to be followed. Relative humidities during ∼1 km (from −11° to −3°C) of the descent were within 4% of ice saturation. It was assumed that the ice particle size distribution was evolving through the process of aggregation alone. Three idealized ice–ice collection kernels were used in a model of ice aggregation and compared to the observed ice particle size distribution evolution: a geometric sweep-out kernel, a Golovin (sum of particle masses) kernel, and a modified-Golovin kernel (sum of particle masses raised to a power). The Golovin kernel performed worst. The sweep-out kernel produced good agreement with the observations when a constant aggregation efficiency of 0.09 was used. The modified-Golovin kernel performed the best and implied that the aggregation efficiency of sub-300-μm particles was greater than unity when compared with a geometric sweep-out kernel.